The Influence of Mineralogy Towards Electrical Resistivity Value and Cation Exchange Capacity
Keywords:Electrical resistivity, Cation exchange capacity, Porosity
Electrical Resistivity Tomography (ERT) is a method used for subsurface profiling in soil. The subsurface profile characterization determines the layer, thickness, soil lithology, presence of groundwater, fracture zones, variations in soil saturation, areas of increased salinity, or groundwater contamination. The value of the subsurface resistivity is determined by using electrical resistivity method (ERM). Multiple factors may influence the analysis results of the electrical resistivity method (ERM), especially the particle size distribution, porosity, mineralogy, density, cation exchange capacity (CEC), and water content. Hence the aim of this study, which was to evaluate the effects of cation exchange capacity (CEC) towards the electrical resistivity values (ERV). The objectives of this study were to characterize index properties of artificial silt and clay at different CEC values, to identify the effect of minerals towards ERV and CEC value, and to establish the correlation of the artificial silt and clay, moisture content, and CEC with the ERV. Samples used in this study were kaolinite, montmorillonite, illite, quartz, mica, and feldspar, passing 0.063mm sieve. Basic soil index properties, i.e., particle size distribution, specific gravity, porosity, and Atterberg limit were determined refering to BS 1377 (1990). A Terrameter LS 2 with a soil resistivity box were used in determining the ERV, whereas Atomic Absorption Spectroscopy (AAS) with ammonium acetate solution to determine the CEC. Porosity obtain from this study were between 0.5 to 0.6. Comparison of mineral based on the ERV obtained shows kaolinite contains the highest resistivity value followed by feldspar, quartz, mica, illite and montmorillonite respectively. The lowest to highest CEC mineral are kaolinite, feldspar, quartz, mica, and illite montmorillonite. These values can correlate between resistivity versus CEC, which shows that the higher the ion exchange, the higher the electrical conductivity of the sample.